/*
* Copyright (C) 2011 University of Washington
* Copyright 1999-2010 The Apache Software Foundation
* Copyright (c) 2005 Brian Goetz and Tim Peierls. See http://www.jcip.net
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package org.odk.collect.android.utilities;
/**
* NOTE: Copied wholesale from Apache HttpComponents 4.1.2 and renamed
* to EnhancedDigestScheme. Implementations prior to 4.1.2 had weak
* cnonce values. Android OS ships with version 4.0.3
*/
/*
* ====================================================================
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
import java.security.MessageDigest;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Formatter;
import java.util.List;
import java.util.Locale;
import java.util.StringTokenizer;
import org.apache.http.Header;
import org.apache.http.HttpRequest;
import org.apache.http.auth.AuthenticationException;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.AUTH;
import org.apache.http.auth.MalformedChallengeException;
import org.apache.http.auth.params.AuthParams;
import org.apache.http.impl.auth.RFC2617Scheme;
import org.apache.http.impl.auth.UnsupportedDigestAlgorithmException;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.message.BasicHeaderValueFormatter;
import org.apache.http.message.BufferedHeader;
import org.apache.http.util.CharArrayBuffer;
import org.apache.http.util.EncodingUtils;
/**
* Digest authentication scheme as defined in RFC 2617. Both MD5 (default) and
* MD5-sess are supported. Currently only qop=auth or no qop is supported.
* qop=auth-int is unsupported. If auth and auth-int are provided, auth is used.
* <p>
* Credential charset is configured via the
* {@link org.apache.http.auth.params.AuthPNames#CREDENTIAL_CHARSET} parameter
* of the HTTP request.
* <p>
* Since the digest username is included as clear text in the generated
* Authentication header, the charset of the username must be compatible with
* the {@link org.apache.http.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET
* http element charset}.
* <p>
* The following parameters can be used to customize the behavior of this class:
* <ul>
* <li>{@link org.apache.http.auth.params.AuthPNames#CREDENTIAL_CHARSET}</li>
* </ul>
*
* @since 4.0
*/
public class EnhancedDigestScheme extends RFC2617Scheme {
/**
* Hexa values used when creating 32 character long digest in HTTP
* DigestScheme in case of authentication.
*
* @see #encode(byte[])
*/
private static final char[] HEXADECIMAL = { '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
/** Whether the digest authentication process is complete */
private boolean complete;
private static final int QOP_UNKNOWN = -1;
private static final int QOP_MISSING = 0;
private static final int QOP_AUTH_INT = 1;
private static final int QOP_AUTH = 2;
private String lastNonce;
private long nounceCount;
private String cnonce;
private String a1;
private String a2;
/**
* Default constructor for the digest authetication scheme.
*/
public EnhancedDigestScheme() {
super();
this.complete = false;
}
/**
* (non-Javadoc)
* @see org.apache.http.impl.auth.AuthSchemeBase#processChallenge(org.apache.http.Header)
*
* Processes the Digest challenge.
*
* @param header
* the challenge header
*
* @throws MalformedChallengeException
* is thrown if the authentication challenge is malformed
*/
@Override
public void processChallenge(final Header header)
throws MalformedChallengeException {
super.processChallenge(header);
if (getParameter("realm") == null) {
throw new MalformedChallengeException("missing realm in challenge");
}
if (getParameter("nonce") == null) {
throw new MalformedChallengeException("missing nonce in challenge");
}
this.complete = true;
}
/**
* Tests if the Digest authentication process has been completed.
*
* @return <tt>true</tt> if Digest authorization has been processed,
* <tt>false</tt> otherwise.
*/
public boolean isComplete() {
String s = getParameter("stale");
if ("true".equalsIgnoreCase(s)) {
return false;
} else {
return this.complete;
}
}
/**
* Returns textual designation of the digest authentication scheme.
*
* @return <code>digest</code>
*/
public String getSchemeName() {
return "digest";
}
/**
* Returns <tt>false</tt>. Digest authentication scheme is request based.
*
* @return <tt>false</tt>.
*/
public boolean isConnectionBased() {
return false;
}
public void overrideParamter(final String name, final String value) {
getParameters().put(name, value);
}
/**
* Produces a digest authorization string for the given set of
* {@link Credentials}, method name and URI.
*
* @param credentials
* A set of credentials to be used for athentication
* @param request
* The request being authenticated
*
* @throws org.apache.http.auth.InvalidCredentialsException
* if authentication credentials are not valid or not applicable
* for this authentication scheme
* @throws AuthenticationException
* if authorization string cannot be generated due to an
* authentication failure
*
* @return a digest authorization string
*/
public Header authenticate(final Credentials credentials,
final HttpRequest request) throws AuthenticationException {
if (credentials == null) {
throw new IllegalArgumentException("Credentials may not be null");
}
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
// Add method name and request-URI to the parameter map
getParameters().put("methodname", request.getRequestLine().getMethod());
getParameters().put("uri", request.getRequestLine().getUri());
String charset = getParameter("charset");
if (charset == null) {
charset = AuthParams.getCredentialCharset(request.getParams());
getParameters().put("charset", charset);
}
return createDigestHeader(credentials);
}
private static MessageDigest createMessageDigest(final String digAlg)
throws UnsupportedDigestAlgorithmException {
try {
return MessageDigest.getInstance(digAlg);
} catch (Exception e) {
throw new UnsupportedDigestAlgorithmException(
"Unsupported algorithm in HTTP Digest authentication: "
+ digAlg);
}
}
/**
* Creates digest-response header as defined in RFC2617.
*
* @param credentials
* User credentials
*
* @return The digest-response as String.
*/
private Header createDigestHeader(final Credentials credentials)
throws AuthenticationException {
String uri = getParameter("uri");
String realm = getParameter("realm");
String nonce = getParameter("nonce");
String opaque = getParameter("opaque");
String method = getParameter("methodname");
String algorithm = getParameter("algorithm");
if (uri == null) {
throw new IllegalStateException("URI may not be null");
}
if (realm == null) {
throw new IllegalStateException("Realm may not be null");
}
if (nonce == null) {
throw new IllegalStateException("Nonce may not be null");
}
// TODO: add support for QOP_INT
int qop = QOP_UNKNOWN;
String qoplist = getParameter("qop");
if (qoplist != null) {
StringTokenizer tok = new StringTokenizer(qoplist, ",");
while (tok.hasMoreTokens()) {
String variant = tok.nextToken().trim();
if (variant.equals("auth")) {
qop = QOP_AUTH;
break;
}
}
} else {
qop = QOP_MISSING;
}
if (qop == QOP_UNKNOWN) {
throw new AuthenticationException(
"None of the qop methods is supported: " + qoplist);
}
// If an algorithm is not specified, default to MD5.
if (algorithm == null) {
algorithm = "MD5";
}
// If an charset is not specified, default to ISO-8859-1.
String charset = getParameter("charset");
if (charset == null) {
charset = "ISO-8859-1";
}
String digAlg = algorithm;
if (digAlg.equalsIgnoreCase("MD5-sess")) {
digAlg = "MD5";
}
MessageDigest digester;
try {
digester = createMessageDigest(digAlg);
} catch (UnsupportedDigestAlgorithmException ex) {
throw new AuthenticationException("Unsuppported digest algorithm: "
+ digAlg);
}
String uname = credentials.getUserPrincipal().getName();
String pwd = credentials.getPassword();
if (nonce.equals(this.lastNonce)) {
nounceCount++;
} else {
nounceCount = 1;
cnonce = null;
lastNonce = nonce;
}
StringBuilder sb = new StringBuilder(256);
Formatter formatter = new Formatter(sb, Locale.US);
formatter.format("%08x", nounceCount);
String nc = sb.toString();
if (cnonce == null) {
cnonce = createCnonce();
}
a1 = null;
a2 = null;
// 3.2.2.2: Calculating digest
if (algorithm.equalsIgnoreCase("MD5-sess")) {
// H( unq(username-value) ":" unq(realm-value) ":" passwd )
// ":" unq(nonce-value)
// ":" unq(cnonce-value)
// calculated one per session
sb.setLength(0);
sb.append(uname).append(':').append(realm).append(':').append(pwd);
String checksum = encode(digester.digest(EncodingUtils.getBytes(
sb.toString(), charset)));
sb.setLength(0);
sb.append(checksum).append(':').append(nonce).append(':')
.append(cnonce);
a1 = sb.toString();
} else {
// unq(username-value) ":" unq(realm-value) ":" passwd
sb.setLength(0);
sb.append(uname).append(':').append(realm).append(':').append(pwd);
a1 = sb.toString();
}
String hasha1 = encode(digester.digest(EncodingUtils.getBytes(a1,
charset)));
if (qop == QOP_AUTH) {
// Method ":" digest-uri-value
a2 = method + ':' + uri;
} else if (qop == QOP_AUTH_INT) {
// Method ":" digest-uri-value ":" H(entity-body)
// TODO: calculate entity hash if entity is repeatable
throw new AuthenticationException(
"qop-int method is not suppported");
} else {
a2 = method + ':' + uri;
}
String hasha2 = encode(digester.digest(EncodingUtils.getBytes(a2,
charset)));
// 3.2.2.1
String digestValue;
if (qop == QOP_MISSING) {
sb.setLength(0);
sb.append(hasha1).append(':').append(nonce).append(':')
.append(hasha2);
digestValue = sb.toString();
} else {
sb.setLength(0);
sb.append(hasha1).append(':').append(nonce).append(':').append(nc)
.append(':').append(cnonce).append(':')
.append(qop == QOP_AUTH_INT ? "auth-int" : "auth")
.append(':').append(hasha2);
digestValue = sb.toString();
}
String digest = encode(digester.digest(EncodingUtils
.getAsciiBytes(digestValue)));
CharArrayBuffer buffer = new CharArrayBuffer(128);
if (isProxy()) {
buffer.append(AUTH.PROXY_AUTH_RESP);
} else {
buffer.append(AUTH.WWW_AUTH_RESP);
}
buffer.append(": Digest ");
List<BasicNameValuePair> params = new ArrayList<BasicNameValuePair>(20);
params.add(new BasicNameValuePair("username", uname));
params.add(new BasicNameValuePair("realm", realm));
params.add(new BasicNameValuePair("nonce", nonce));
params.add(new BasicNameValuePair("uri", uri));
params.add(new BasicNameValuePair("response", digest));
if (qop != QOP_MISSING) {
params.add(new BasicNameValuePair("qop",
qop == QOP_AUTH_INT ? "auth-int" : "auth"));
params.add(new BasicNameValuePair("nc", nc));
params.add(new BasicNameValuePair("cnonce", cnonce));
}
if (algorithm != null) {
params.add(new BasicNameValuePair("algorithm", algorithm));
}
if (opaque != null) {
params.add(new BasicNameValuePair("opaque", opaque));
}
for (int i = 0; i < params.size(); i++) {
BasicNameValuePair param = params.get(i);
if (i > 0) {
buffer.append(", ");
}
boolean noQuotes = "nc".equals(param.getName())
|| "qop".equals(param.getName());
BasicHeaderValueFormatter.DEFAULT.formatNameValuePair(buffer,
param, !noQuotes);
}
return new BufferedHeader(buffer);
}
String getCnonce() {
return cnonce;
}
String getA1() {
return a1;
}
String getA2() {
return a2;
}
/**
* Encodes the 128 bit (16 bytes) MD5 digest into a 32 characters long
* <CODE>String</CODE> according to RFC 2617.
*
* @param binaryData
* array containing the digest
* @return encoded MD5, or <CODE>null</CODE> if encoding failed
*/
private static String encode(byte[] binaryData) {
int n = binaryData.length;
char[] buffer = new char[n * 2];
for (int i = 0; i < n; i++) {
int low = (binaryData[i] & 0x0f);
int high = ((binaryData[i] & 0xf0) >> 4);
buffer[i * 2] = HEXADECIMAL[high];
buffer[(i * 2) + 1] = HEXADECIMAL[low];
}
return new String(buffer);
}
/**
* Creates a random cnonce value based on the current time.
*
* @return The cnonce value as String.
*/
public static String createCnonce() {
SecureRandom rnd = new SecureRandom();
byte[] tmp = new byte[8];
rnd.nextBytes(tmp);
return encode(tmp);
}
}